1. Field of the Invention
The present invention relates to a tire chuck apparatus and method for gripping a tire from the inner side of the bead portion.
2. Description of the Related Art
Unprocessed tires and vulcanized tires (finished products) are generally gripped for various reasons. Tires are gripped in order to insert or take out a tire in a vulcanizing mold in a tire manufacturing process, or in order to collect and ship tires in a physical distribution process, or in order to be shipped in or out in a sales process.
A known conventional chuck apparatus for gripping tires in these types of processes is one provided with, for example, a supporting member capable of moving in the central axial direction of the tire and at least two gripping claws supported by the supporting member such that the gripping claws can expand and contract in the radial direction of the tire. In this chuck apparatus, by moving the supporting member in the central axial direction of the tire when each of the gripping claws is contracted in the radial direction of the tire, each gripping claw is inserted within the tire bead portion of a tire placed horizontally on a roller conveyor, loading stand, or the like. By then expanding each of the gripping claws in this state in the radial direction of the tire, the tire bead portion is gripped from the inner side.
However, in this type of conventional tire chuck apparatus, the problem arises that the tire is sometimes gripped in a state in which the center of the tire is out of position. The reason for this occurring is described below.
Namely, if the central axis of the tire and the center of the chuck apparatus gripping the tire (the center of a single circle running through all the gripping claws) are not aligned, when the gripping claws expand in the radial direction of the tire, the gripping claws contact the internal periphery of the tire bead portion one after the other with a small time difference between each contact. If, at this time, the amount of friction resistance between the tire and the roller conveyor or loading stand is large enough that the tire is unable to move, the tire bead portion is pushed by the gripping claw which makes contact first and is slightly deformed in portions. As a result, the tire ends up being gripped by the gripping claws in a state in which the central axis of the tire is not aligned with the center of the chuck apparatus.
Furthermore, because the above described gripping claws only hold the tire as it is and cannot rotate the tire, when performing an inspection over the entire periphery of the tire, it is necessary to rotate the inspection apparatus or the like around the periphery of the tire which results in the problem that the apparatus as a whole is large and expensive.
The aim of the present invention is to provide a tire chuck apparatus and method in which the size of the apparatus can be reduced and the cost thereof decreased and at the same time gripping of a tire by gripping mechanism at a misaligned position can be reduced.
In order to achieve the above objectives, the first aspect of the present invention is a tire chuck apparatus for holding a tire having a tire bead, the apparatus including a gripping mechanism with at least two gripping members movable in tire radial direction from a retracted position to an extended position for pressing against the inner side of the bead portion of the tire and thereby holding the tire, gripping rollers as the gripping members adapted to be rotatable around an axis substantially parallel to a central axis of the tire, and a rotation drive mechanism for rotating the tire around the central axis of the tire.
In the above aspect, when gripping a tire, firstly, each gripping roller (gripping member) which has been moved to the inner side in the radial direction of the tire is inserted along the central axis of the tire into the inner side of the tire bead portion. From this state, each gripping roller is then expanded to the outer side in the radial direction of the tire. If the central axis of the tire is not aligned with the central axis of the chuck apparatus (the center of a single circle passing through all of the gripping rollers) at this point, the gripping rollers make contact one after another with the inner periphery of the tire bead portion with a short time difference between the contact by each roller.
If the tire is unable to move at this time, the tire bead portion begins to undergo slight partial deformation as it is pushed by the gripping claw which makes the first contact. In the present invention, however, by rotating the tire around its central axis using the rotation drive means, the tire is shifted to a position in which all of the gripping rollers make contact with the inner periphery of the tire bead portion.
At this point, because the gripping rollers contacting the tire bead portion rotate around an axis parallel to the central axis of the tire, the gripping rollers do not hinder the rotation of the tire. As a result, a movement of the tire such as that described above can take place easily and smoothly. Because of this, the above described deformation is prevented and the result of this is that mispositioning between the central axis of the tire and the center of the chuck apparatus is reduced. In short, the tire is gripped from the inside by the gripping rollers in a state in which the central axis of the tire has been accurately positioned relative to (coincided with) the center of the chuck apparatus.
Furthermore, after the tire has been gripped by the gripping rollers, if the tire is rotated around the central axis thereof by the rotation drive mechanism, it is possible to perform an inspection or the like over the entire periphery of the tire even if the inspection apparatus is stationary. As a result, there is no need to rotate the inspection apparatus or the like around the periphery of the tire enabling the size of the apparatus overall to be reduced and the production costs to be decreased. The inspection apparatus mentioned above may be a tire information reading mechanism, a surface condition reading mechanism, an internal condition reading mechanism, and the like.
In the second aspect of the present invention, a tire is rotated by at least one gripping roller being rotated by the rotation drive mechanism.
The structure of the second aspect enables the gripping rollers to also be used for the rotation of the tire which allows the structure to be simplified. Moreover, because the rotation force in the peripheral direction is applied from the gripping rollers to the bead portion which is the portion of a tire with the highest rigidity, the rotation of the tire can be accurately controlled.
In the third aspect of the present invention, a tire is rotated by all gripping rollers being rotated by the rotation drive mechanism.
The structure of the third aspect enables rotation force to be continuously applied to the tire from the time the first gripping roller makes contact with the tire bead portion. The result of this is that the alignment of the central axis of the tire with the center of the chuck apparatus is smoothly carried out.
In the fourth aspect of the present invention, the drive source of the rotation drive mechanism is placed in a central space (position) surrounded by gripping rollers.
The structure of the fourth aspect allows effective use to be made of empty space.
In the fifth aspect of the present invention, the tire information reading mechanism, the surface condition reading mechanism, the internal condition reading mechanism, or the like is attached to a member which moves in the central axial direction of the tire integrally with the gripping roller.